The present invention relates to a liquid crystal display (LCD), and more specifically, to an LCD adopting gate driver on array (GOA) circuit.
A GOA circuit makes use of the thin-film transistor liquid crystal display (TFT-LCD) array process to form a gate driver on a GOA substrate with TFT arrays to realize a driving method of progressive scan.
A GOA circuit comprises a plurality of GOA circuit units. When a gate enabling signal turns on all GOA circuit units, scan signals outputted by each GOA circuit unit to scan lines remain at a low level. If a scan signal of a scan line cannot change from being at a low level to a high level before a clock signal arrives, the normal operation of GOA circuit units will be affected.
More specifically, a stage transmission signal inputted by a third stage GOA circuit unit is a scan signal outputted by a first stage GOA circuit. Therefore, the status of the scan signal of the first stage GOA circuit unit will affect the operation status of the third stage GOA circuit unit. Before the third stage GOA circuit unit receives a clock signal, the scan signal from the first stage GOA circuit unit is kept at a low level by a load capacitor. When a clock signal is received, the third stage GOA circuit unit is affected by the low level of the scan signal of the first stage GOA circuit unit, so that the third stage GOA circuit unit starts operating earlier than the first stage GOA circuit unit. It means that there is a redundant pulse in the scan signal outputted by the third stage GOA circuit unit. The redundant pulse will follow the stage transmission of the scan signal and affect the scan signal of the next stage GOA circuit unit. Moreover, all GOA circuit units controlled by the same clock signal, such as the third, seventh, eleventh or other circuit units will generate scan signals with redundant pulses, compromising the whole GOA circuit.
Therefore, how to form a GOA circuit that generates scan signals without redundant pulses is a goal that the industry should work on.